Various areas of communication, be they Wi-Fi or long term evolution (LTE), use the orthogonal frequency division multiplexed (OFDM) modulation technique. Smart grid networks, where smart meters are measuring energy consumption and transmitting that information to central processing stations, are also moving towards OFDM-based communications. Two examples of smart grid communications are smart utility networks (SUN), which is a wireless communication technology, and power line communications (PLC), which is a wired communication technology. These communication systems are governed by various regulatory agencies that put limits on various aspects of the transmissions, including out-of-band emissions (OOB).
OFDM modulation forms information into symbols and/or packets of symbols with each symbol comprising various numbers of sub-carriers. The sub-carriers are used to transmit a bit(s) of information and each sub-carrier may be associated with a different frequency. When using OFDM modulation, a discontinuity may form at the transition from one OFDM symbol to the next. These discontinuities may increase the OOB emissions, an area highly regulated by several regulatory bodies, including the Federal Communication Commission (FCC). The FCC requires OOB emissions to be minimal.